Method of preparing polyvinyl acetal ketal resins



Patented Aug. 24, 1948 UNITED STATES"! PATENTI- orrics M'E'mon orraaraamo POLYVINYL ACE'IAL KETAL aasms Joseph D. Ryan, Toledo, Ohio, andFred B. Shaw,

Jr., Baltimore, Md.,'a'aaignors toLibhey-Owens- Ford Glass Company,Toledo, Ohio, a oorporation of Ohio I No Drawing. Application January30, 1943,

' Serial No. "180 .Dltinii- (01. 26MB) Gui invention relates toa newmethod for the Asia specific method of carrying out our inpreparation:otapoiyvinyl acetal ketal resins. vention, the following procedure isoutlined:

' structurally, the'polyvinyl acetal ,ketai resins, I 132 grams oipolyvinyl butyral-resin-analyzing I contain. as basic groups. within theaamemole follows; 7 cule,vinyi acetalgroiipavinylketal groups, vinyl 6ler cent alcohol groupst'and vinyl estergroups. for the Vinyl alcohol(calculated as polyvinyl '19 1 preparation or polyvinyl acetal ketalresins by our 3 alcohol) method, any particular aldehyde or retain mayVinyl t- (calculated as polyvinyl o be employed. 7 v tate) 1.15

The resins-of our invention aresuperior to and m Vinyl butyral(calculated a P yv nyl are intended to replace the polyvinyl acetairesins butyial) '79 3 which are at Present the W wasdissolved in "(50cc. of methanol. 500 cc. laminated. safety glass. photographic iiiimethyi isobutyiketone and 400 cc. of methanolicfabrics-mv 110112.75normal) were added and the mixture Prior to invenimnn i ailowed tostand-for 24 hours. At the end of 24 resins have been prepared by 9;hours. the mixture had formed a hard gel. 500 cc.

mm-amt polyvinyl esters more'parflcua'fly poly of normal .hutyraidehydewas added and the vinyl acetate- In h 18mm described in the whole wasstirred until the gel went into solution. prior the Polyvinyl ester issubjected to m The resin was then precipitated by throwing the partialhydrolysis and the desired ketone added aohmon mm water. The resinproduct was then and reacted with one of the hydroxyl groups filteredoil, washed free 0! acid catalyst, and formed by the hydrolysis process.At this stage, mat a the desired aldehyde in proper proportion is oAnalysis of the product: Per cent grllgegnand reaction then allowed togo to em 5 vinyl acetate (calcuated as p y y In the method of ourinvention, we start with acetate) a polyvinyl acetal resin instead ofemploying a vinyl who! (calculated Wlyvmyl polyvinyl ester. To carry outour process, the n desired polyvinyl 'acetal resin is dissolved in anvinyl new?! 150mm? ketal (calculated anhydrous medium in the presence ofa catalyst 1 as Polyvinyl methyl isobutyl ketal) 50-82 and the ketone tobe reacted is added in the vinyl butwal (mug-ted as Polyvinyl 37 properproportions and the mixture allowed to butyml) stand. preferably at roomtemperature, care be- Another specific method for carrying out our ingtaken to control the time of reaction to ob- I invention is as follows:

tain a resin having the desired analysis. In 135 trams of polyvinylformal resin analyzing some cases, mixtures of aldehyde and ketones asiollows: may replace the lietone alone. j V Per cent We have foundthatthe compositions oi'the inyl i i a ulat d as p l i yl i'esins madeby our method can be varied by vary- 40 mal) 82 ing the ratio ofaldehyde to ketone used and also vinyl 811001101 (calculated as P y ya100- by varying the ratio of the total weight or the i101) s 'zaldehyde and ketone employed to the weight of Vinyl acetate (calculatedas polyvinyl c origi'nal resinous starting material. we have l 2 furtheiestablished that the T3910 of i were dissolved in 1000 cc. of ethylenedichloride.

aldehyde in the finished resin can be governed 3 0 of methyl ethyl k twas added, 1.. by add n the ketone fi s d t n s n ns th lowed by theimmediate addition of 100 cc. of amount or time the mixture is allowedto stand methanoiic hydrochloric acid (4.6 normal). The before theaddition 0! more aldehyde. Contrary mixture was allowed to stand for 6hours. At to what would normally be expected in such a the end of thisperiod, the ethylene dichloride chemical reaction, the longer themixture of polywas removed by distillation and the residue vinyl aoetalresin, catalyst, aldehyde and ketone diluted with water, whereupon itprecipitated are allowed to stand, after a short initial period,therefrom. This precipitated resin product was the more free hydroxylgroups are found in the filtered ofl, washed free of acid catalyst anddried. resin material. so .On analysis, the product was shown to have avinyl alcohol content (calculated as polyvinyl alcohol) of 18.8% and avinyl acetate content (calculated as polyvinyl acetate) of 7.5%.

Still another resin was formed in accordance with the followingprocedure:

135 grams of po yv yl acetal resin made by reacting partially hydrolyzedpolyvinyl acetate with acetaldehyde and analyzing as follows:

Per cent Vinyl acetate (calculated as polyvinyl acetate) 1 29.1 Vinylalcohol (calculated as polyvinyl alcohol) 9.5

Vinyl acetaTEchTlhhEtdz 56.8 was dissolved in 1000 cc. of methanol. ofdi-lsobutyl ketone was then added,

the mixture into water with rapid stirring. The

resin product was recovered by filtration, washed free of acid by water,and then dried. The product analyzed as follows:

very small number of the available hydroxyl groups is replaced by ketalgroups. For this reason, it has been difficult to introduce a largenumber of ketal groups into the resins by ordinary methods. Using ournew process, we have been able to introduce large proportions of ketalgroups into the finished polyvinyl acetal ketal resin by an exchangereaction which apparently is a reversible chemical equilibrium and inwhich the ratio of ketal groups and acetal groups can be varied widelyby proper control of the amount of catalyst, concentration, ratio ofketone added, as well as the time of reaction.

tlon of large numbers of ketal groups, we have been able to produceresins having new and out standing properties. Likewise, we have foundan advantage in being able to use a higher ratio of ketone to aldehyde,for, in general, the ketones are as a class cheaper than the aldehydescustomarily mployed,

As catalysts for carrying out our method, we have found that a materialof an acidic nature should be used. For example, hydrochloric acid,hydrogen-chloride, sulphuric acid, phosphoric and halide salts haveproved successful. Halide salts preferably should be those metals thatform weak bases, such as aluminum chloride, tin chloride, or evenmaterials like boron triiluoride.

- Weclaim:

1. The method of preparing a polyvinyl acetal ketal resin, comprisingreacting a polyvinyl acetal resin from a saturated aliphatic aldehyde inan anhydrous neutral organic solution and in the presence of aninorganic condensation catalyst of acid reaction with saturated ketone,allowing the reaction to proximately room temperature, covering theresin product.

2. The method of preparing a polyvinyl acetal ketal resin, comprisingreacting a polyvinyl acetal resin from a saturated aliphatic aldehyde inan anhydrous neutral organic solution and in the presence of aninorganic condensation catalyst of acid reaction with a saturatedaliphatic monoketone, subsequently adding a saturated aliphaticmonoaldehyde, allowing the reactions to proceed at approximately roomtemperature, and finally recovering the resin product.

3. The method of preparing polyvinyl acetal ketal resins, comprisingdissolving a polyvinyl acetal resin from a saturated aliphatic aldehydein an anhydrous neutral organic medium, adding a saturated aliphaticmonoketone and an inorganic condensation catalyst of acid reaction,allowing the reaction to proceed at approximately room temperature, andthen recoveringthe resin product.

4. The method of preparing polyvinyl acetal ketal resins, comprisingdissolving a polyvinyl acetal resin from a saturated aliphatic aldehydein an anhydrous neutral organic medium, adding a saturated aliphaticmonoketone, an inorganic condensation catalyst sequently a saturated andan aliphatic monoaldehyde, allowing the reactions to proceed atapproximately room temperature, and finally recovering the resinproduct.

.The following references are of record in the file of this patent:

UNITED STATES PATENTS proceed at anand then re- -Number Name Date2,227,975 Kenyon et al. Jan. 7, 1941 2,310,943 Dorough et al. Feb. 16,1943 2,341,306 Agre et al. Feb. 8, 1944 I FOREIGN PATENTS Number CountryDate 483,222 Great Britain Apr. 8, 1938 842,066 France Feb. 20, 1939 ofacid reaction and sub Certificate of Correction Patent No. 2,447,7 73.August 24, 1948.

JOSEPH D. RYAN ET AL.

It is hereby certified that errors appear in the printed specificationof the above I numbered patent requiring corrections as follows: Column4, line 14, claim 1, before the Word saturated insert a; line 43, claim4, strike out the words and an; and], that the said Letters Patentshould be read with these corrections therein that th same may conformto the record of the case in the Patent Ofiice.

Signed and sealed this 9th day of November, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commz'ssioner of Patents.

